| Message ID | 20230306224127.1689967-7-vipinsh@google.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | NUMA aware page table allocation | expand |
On Mon, 6 Mar 2023 14:41:15 -0800 Vipin Sharma <vipinsh@google.com> wrote: > Use MMU shrinker to free unused pages in split_shadow_page_cache. > Refactor the code and make common function to try emptying the page cache. > > Signed-off-by: Vipin Sharma <vipinsh@google.com> > --- > arch/x86/kvm/mmu/mmu.c | 34 +++++++++++++++++++++------------- > 1 file changed, 21 insertions(+), 13 deletions(-) > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > index 0ebb8a2eaf47..73a0ac9c11ce 100644 > --- a/arch/x86/kvm/mmu/mmu.c > +++ b/arch/x86/kvm/mmu/mmu.c > @@ -6696,13 +6696,24 @@ void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm, u64 gen) > } > } > After adding the lock in the kvm_mmu_memory_cache, the cache_lock doesn't need to be passed here and in mmu_shrink_scan(). > +static int mmu_memory_cache_try_empty(struct kvm_mmu_memory_cache *cache, > + struct mutex *cache_lock) > +{ > + int freed = 0; > + > + if (mutex_trylock(cache_lock)) { > + freed = cache->nobjs; > + kvm_mmu_empty_memory_cache(cache); > + mutex_unlock(cache_lock); > + } > + return freed; > +} > + > static unsigned long mmu_shrink_scan(struct shrinker *shrink, > struct shrink_control *sc) > { > struct kvm *kvm, *next_kvm, *first_kvm = NULL; > - struct kvm_mmu_memory_cache *cache; > unsigned long i, freed = 0; > - struct mutex *cache_lock; > struct kvm_vcpu *vcpu; > > mutex_lock(&kvm_lock); > @@ -6716,18 +6727,15 @@ static unsigned long mmu_shrink_scan(struct shrinker *shrink, > list_move_tail(&kvm->vm_list, &vm_list); > > kvm_for_each_vcpu(i, vcpu, kvm) { > - cache = &vcpu->arch.mmu_shadow_page_cache; > - cache_lock = &vcpu->arch.mmu_shadow_page_cache_lock; > - if (mutex_trylock(cache_lock)) { > - if (cache->nobjs) { > - freed += cache->nobjs; > - kvm_mmu_empty_memory_cache(cache); > - } > - mutex_unlock(cache_lock); > - if (freed >= sc->nr_to_scan) > - goto out; > - } > + freed += mmu_memory_cache_try_empty(&vcpu->arch.mmu_shadow_page_cache, > + &vcpu->arch.mmu_shadow_page_cache_lock); > + if (freed >= sc->nr_to_scan) > + goto out; > } > + freed += mmu_memory_cache_try_empty(&kvm->arch.split_shadow_page_cache, > + &kvm->slots_lock); > + if (freed >= sc->nr_to_scan) > + goto out; > } > out: > mutex_unlock(&kvm_lock);
On Thu, Mar 9, 2023 at 8:01 AM Zhi Wang <zhi.wang.linux@gmail.com> wrote: > > On Mon, 6 Mar 2023 14:41:15 -0800 > Vipin Sharma <vipinsh@google.com> wrote: > > > Use MMU shrinker to free unused pages in split_shadow_page_cache. > > Refactor the code and make common function to try emptying the page cache. > > > > Signed-off-by: Vipin Sharma <vipinsh@google.com> > > --- > > arch/x86/kvm/mmu/mmu.c | 34 +++++++++++++++++++++------------- > > 1 file changed, 21 insertions(+), 13 deletions(-) > > > > diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c > > index 0ebb8a2eaf47..73a0ac9c11ce 100644 > > --- a/arch/x86/kvm/mmu/mmu.c > > +++ b/arch/x86/kvm/mmu/mmu.c > > @@ -6696,13 +6696,24 @@ void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm, u64 gen) > > } > > } > > > > After adding the lock in the kvm_mmu_memory_cache, the cache_lock doesn't need > to be passed here and in mmu_shrink_scan(). > Agree. Let us see what is the decision on moving the lock inside the cache.
diff --git a/arch/x86/kvm/mmu/mmu.c b/arch/x86/kvm/mmu/mmu.c index 0ebb8a2eaf47..73a0ac9c11ce 100644 --- a/arch/x86/kvm/mmu/mmu.c +++ b/arch/x86/kvm/mmu/mmu.c @@ -6696,13 +6696,24 @@ void kvm_mmu_invalidate_mmio_sptes(struct kvm *kvm, u64 gen) } } +static int mmu_memory_cache_try_empty(struct kvm_mmu_memory_cache *cache, + struct mutex *cache_lock) +{ + int freed = 0; + + if (mutex_trylock(cache_lock)) { + freed = cache->nobjs; + kvm_mmu_empty_memory_cache(cache); + mutex_unlock(cache_lock); + } + return freed; +} + static unsigned long mmu_shrink_scan(struct shrinker *shrink, struct shrink_control *sc) { struct kvm *kvm, *next_kvm, *first_kvm = NULL; - struct kvm_mmu_memory_cache *cache; unsigned long i, freed = 0; - struct mutex *cache_lock; struct kvm_vcpu *vcpu; mutex_lock(&kvm_lock); @@ -6716,18 +6727,15 @@ static unsigned long mmu_shrink_scan(struct shrinker *shrink, list_move_tail(&kvm->vm_list, &vm_list); kvm_for_each_vcpu(i, vcpu, kvm) { - cache = &vcpu->arch.mmu_shadow_page_cache; - cache_lock = &vcpu->arch.mmu_shadow_page_cache_lock; - if (mutex_trylock(cache_lock)) { - if (cache->nobjs) { - freed += cache->nobjs; - kvm_mmu_empty_memory_cache(cache); - } - mutex_unlock(cache_lock); - if (freed >= sc->nr_to_scan) - goto out; - } + freed += mmu_memory_cache_try_empty(&vcpu->arch.mmu_shadow_page_cache, + &vcpu->arch.mmu_shadow_page_cache_lock); + if (freed >= sc->nr_to_scan) + goto out; } + freed += mmu_memory_cache_try_empty(&kvm->arch.split_shadow_page_cache, + &kvm->slots_lock); + if (freed >= sc->nr_to_scan) + goto out; } out: mutex_unlock(&kvm_lock);
Use MMU shrinker to free unused pages in split_shadow_page_cache. Refactor the code and make common function to try emptying the page cache. Signed-off-by: Vipin Sharma <vipinsh@google.com> --- arch/x86/kvm/mmu/mmu.c | 34 +++++++++++++++++++++------------- 1 file changed, 21 insertions(+), 13 deletions(-)